Shroud of Turin

      It's Easter and as expected the Shroud of Turin takes on considerable interest at this time. Many people believe that this artifact is the actual burial cloth of Jesus.  Why?  This linen cloth bears the image of a man who appears to have suffered physical trauma in a manner consistent with crucifixion. Since first observed in 1898 by amateur photographer Secondo Pia in the Turin Cathedral, scientists, theologians, historians and researchers have been debating the origins and nature of mysterious image. The Catholic Church has neither formally endorsed nor rejected the shroud.

      Naturally, our position on the cloth is consistent with that put forth by Joe Nickell, Ph.D., Senior Research Fellow of the Committee for Skeptical Inquiry (CSI) and "Investigative Files" columnist for Skeptical Inquirer, as expressed in his book Inqueston the Shroud of Turin (1998). In a 2004 update to this research appearing in the Skeptical Enquirer.

Science has proved the Shroud of Turin a medieval fake, but defenders of authenticity turn the scientific method on its head by starting with the desired conclusion and working backward to the evidence—picking and choosing and reinterpreting as necessary. 

      Without a doubt Dr Nickell is likely to be biased, as some of his detractors like to accuse, but as a Fellow of CSI, he is likely more than others to be alert to confirmation bias. However, what many people not familiar with CSI don't know, is that skeptics of this academic organization are also open to the critique of other skeptics.  That's what scientific skepticism does. There are no sacred cows. The following comments from the Skeptics Dictionary gives some insight into this process"

Because so many "extraordinary" or "weird" claims are based on a poor understanding of perception, memory, testimony, and science, it is only natural that scientific skepticism involves the promotion of science and critical thinking. . . is not in the business of debunking for debunking's sake or of denying for denying's sake. . . Denialism, is not a part of scientific skepticism. . . Scientific skepticism recognizes that even though some uncertainty may exist, the sum of the evidence may preponderantly support some claims. A reasonable person accepts what is most likely the case rather than demanding that we not give our assent to any proposition until one can say there is no doubt that this is the case. Critical thinkers recognize that the precautionary principle can be paralyzing. Science may not be immune to error and it may not provide us with infallible truth, but it is the best method we've discovered so far for getting at the most reasonable beliefs about the world we live in.

After a series of email exchanges on this topic, David Irvine, as skeptic of the above skeptic, offered

I'm going to stay with the Occam's Razor principle, namely that the simplest explanation is probably the most likely, namely that the Shroud is what it appears to be: the burial cloth of a crucified man whose image was transferred to the cloth by some as yet undetermined mechanism which so far has not been successfully duplicated in all its properties.  Regarding whether that man was Jesus gets into the realm of speculation but it certainly seems plausible.  I understand that the sale of religious relics was quite popular in the Middle Ages, and as one wit observed (Mark Twain perhaps?), if all the fragments of the "True Cross" were gathered together one would have an entire forest.  But as far as I know this Shroud is unique; I've never heard of anything like it turning up anywhere else; other shrouds yes, but not with images on them.

      The principle of Occam's razor is usually interpreted to mean "the simpler the explanation, the better" or "don't multiply hypotheses unnecessarily."  Stay what is clearly evident and don't add that which is not.  Our best science says the cloth has materials dating between the 13th and 15th centuries.  There is no evidence that it was ever used as a burial cloth. That is supposition. The image was applied by unknown means between this material date and 1898.  No one knows when, how, or why it was actually applied.  Our dating techniques tell nothing about the image.  Claims that the image on the cloth is that that of Jesus is pure supposition back by nothing. No physical description of Jesus is contained in any of the canonical Gospels.
      What is known about the time between when the cloth was most likely weaved and 1898 was that the selling of relics was big business.  David's comment of fragments of the cross is accurate.  Also, materials suitable for art were rare.  Artists used whatever they could find including old works which they commonly covered and reused.
     The simplest solution to the shroud based on what is known to be facts is the linen sheet very likely was used by some artist.  The image degraded over five centuries of exposure.